Thanks for the post. Before increasing the JVM would like to see if you are getting warning message at stuck thread or any kind of error at weblogic.
Please share the log if any so that we can check and troubleshoot.
Also check - Oracle HTTP Server 126.96.36.199.0 Excessive CPU Usage (Doc ID 1625508.1)
If you still see any issues would recommend to raise an SR or in TEST instance try to increase the JVM to 3GB and test.
How much RAM does your application server have?
How many concurrent users are accessing EBS?
What is 450 active concurrent request? Is that how many run each hour or you have 450 running concurrent requests?
Is this running in a virtual environment? If so, are you sure the hypervisor is properly tuned for nigh volume processing? Out of the box, no hypervisor is.
Increasing JVM RAM/HEAP does not reduce garbage collection.
Getting Optimal Performance from Oracle E-Business Suite [CON6711]
Please review the following section:
Size The Middle Tier For Concurrency (JVM Heaps)
• Total available memory is the most important factor affecting GC performance.
• Monitor the frequency of collections, especially major collections (i.e. Full GC)
• Enable verbose GC to tune heap sizes based on the GC traffic
• Start with:-Xms2048M and –Xmx2048M
• Setting -Xms and -Xmx to the same value avoids the need for heap memory re-allocation during runtime
• Consider using jstat to monitor and review each of the heap generations for possible tuning
• Increase the number of JVMs to scale up for more users with faster GC times. – Each JVM has a smaller Xmx,Xms memory footprint so full GCs will be faster!